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प्रश्न
What is an indicator?
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उत्तर
An acid-base indicator is a chemical substance that indicates the acidic or basic nature of a solution by a suitable colour change.
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संबंधित प्रश्न
A milkman adds a very small amount of baking soda to fresh milk. Why does he shift the pH of the fresh milk from 6 to slightly alkaline?
Those substances whose smell (or odour) changes in acidic or basic solutions are called ______ indicators.
Onion and vanilla extract are ______ indicators.
Two solutions X and Y are tested with universal indicator. Solution X turns orange whereas solution Y turns red. Which of the solutions is a stronger acid?
The pH values of three acids A, B and C having equal molar concentrations are 5.0, 2.8 and 3.5 respectively. Arrange these acids in order of the increasing acid strengths.
Name two common antacids.
Here are some results of solutions tested with universal indicator paper:
| Sulphuric acid | : | Red |
| Metal polish | : | Dark blue |
| Washing-up liquid | : | Yellow |
| Milk of magnesia | : | Light blue |
| Oven cleaner | : | Purple |
| Car battery acid | : | Pink |
Arrange the solutions in order of their increasing pH values (starting with the one with the lowest pH).
A group of students measured the pH of some substances they found in their homes. Their results are given in the following table:
| Substance | pH | Substance | pH |
| Apples | 3.0 | Salt | 7.0 |
| Baking soda | 8.5 | Sugar | 7.0 |
| Black coffee | 5.0 | Toothpaste | 9.0 |
| Household ammonia | 12.0 | Vinegar | 3.0 |
| Lemon juice | 2.5 | Washing soda | 11.5 |
| Milk | 6.5 |
- What would the students have used to measure the pH?
- Which solution is the most acidic?
- Which solution is the most alkaline?
- Which solutions are neutral?
- Which solution can be used to treat wasp stings?
- Which solution can be used to treat bee stings?
Turmeric is used as a _______.
What is the colour of phenolphthalein in the basic solution?
